Protective apparatus for radiotelegraphic stations.



E. GIRARDEAU.

PROTECTIVE APPARATUS FOR RADIOTELEGRAPHIC STATIONS.

APPLICATION FILED MAY 26, 1911.

1,035,958. I Patented Aug.20,1912.

Fig.1.

At tor neg.

EMILE 'GIRARDEAU, OF PARIS, FRANCE.

PROTECTIVE APPARATUS FOR RADIOTELEGRAPHIC STATIONS.

Specification of Letters Patent.

Patented/\ug. 20, 1912'.

Application filed May 26, 1911. Serial No. 629,686.

To all whom 1' t may concern.

Be it known that. I, can. (luc'mnrnw, a

citizen of the Republic of France, residing antenna'A isfexcit'edindirectly by means of at Tesla transformer 1. S and is connected toearth by the intermediary of a gap C from the terminals (.f which theprimary of the reception jigger J is branched, its secondary circuitbeing closed upon the detector I). In these conditions if the.transmitting apparatus does not work and if the electromagnetic wavescoming from an operative station excite the antenna A the gap C does notpermit ofthe direct passage of the current then circulating.between thisantenna and the earth and this current being obliged to circulate in theprimary of the jigger J the signals emitted from the transmittingstation are recorded by the detector I). It,

on the other hand, the station is rendered operative by means of theoscillating circuit containing the sparkgap I and the primary 1" of theTesla transformer and it the sparking distance in C is sufficientlysmall a spark is struck: bet-ween the eiectrcdes of this gap and shortcircuits the primary of the jigger at the terminals of which the tensioncannot in any case exceed the mine corresponding 40 to the sparkingdistance in C. This distance, cannot, however, be reduced beyond acertain value without set-ting up a permanent short circuit in 'C, forexample, owing to a deposit produced by the passage. of the spark, adeformation of the electrodes and so forth. It. follows that thedetector D should be relatively strong, that is to say, in general notvery sensitive. as it. should not be injured when a tensioning of thenature of the magnitude of the sparking tension of the break is appliedto the terminals of the primary of the jigger J. The arrangementcontemplated by the present invention obviates this defect. and rendersit possible to employ sensitive detectors.

Figs. 1 and 2 of the accompanying draw ing represent two diagrams of myimproved arrangement.

From the labors of H. Hertz and other experimenters it is known that theexplosive potential of a spark gap is lowered considerably by theactioii of ultra-violet. light. This ultra-violet light. can befurnished by an;oscillating spark, a vacuum tube and so forth.Aecm-dingly if the break is located (l lig. t) in proximity to the sparkgap I itself of the primary oscillating emission circuit when this gapbecomes operative it autonmtically lowers the explosive potential in andemisequentlv largely re duces the strain on the. detector I). Instead ofutilizing the infllience of the gap E directly a vacuum tube or a. neontube '1 (Fig. 2) can. be employed for example being branched either offthe extremities of a portion of the. primary circuit or of the secondaryCllCllltZOl' even otf the terminals of the gap'E and so on. ()bviousiythe illumination. of this tube during the operation of the emissionsystem produces the desired effect. r.

It will be obvious that numerous modifications may be devised withoutaltering the principle of the invention; when the method of mountingillustrated. in Fig. 2 is employed for example the tube T can befurnished with a tension limiting device.

What I claim and desire to secure by Letters Patent of the United Statesis z- 1. In a radio-telegraph station, a receiving apparatus, atransmitting apparatus, a device including a spark gap for protectingthe receiving apparatus from the waves radiating from the transmittingapparatus, and means for generatin ultra-violet rays of light inproximity to t e spark gap.

2. A receiving apparatus in a radio-tele- I graph system including meansfor detect-- mg waves froma distant'station, a device including a sparkgap for protecting said apparatus from the-waves transmitted at its ownstation, and means generating and utili'zingthe action of ultra-violetrayspf light upon said spark gap.

In a radio-telegraph system a 'receiv-' ing apparatus, a transmittingapparatus ineluding a spark gap,,means including a spark-gap forprotecting said receiving apparatus from the waves of said transmittingapparatus disposed with said spark gap in" such proximity to the sparkgap of the transmitting apparatus that the spark gap paratus- J .of theProtecting means is subject to the aeand means whereby said transmittinga 10 tion 0 the ultra violet rays generated by pmtus generatesultraviolet rays of lig t thespark-.gep of the transmitting epf 1nroximity to said spark up.

" ntestimony whereofln my signature 5 4. In a radio-telegraph system, areceiw. inpremnoe of two witnesses.

in; epperatum'eitransmitting eppmtuq-u' EMILE GIRARDEAU.

devicemcluding e spmk gm for rotectibg said receiving apparatus om t ewaves H. C. Coxn,

genera ted'hy said transmitting apparatus, Jomw BA'linn. 1

